Africanized honeybees have turned up in Colorado, officials said last week, surprising
scientists who previously doubted that they could survive winters at northern latitudes.

The Mesa County Health Department said that a peach grower contacted authorities last month to
report abnormally aggressive behavior at a beehive in his orchard in Palisade, Colo., about 45
miles east of the Utah border.

Specimens were shipped to a U.S. Department of Agriculture laboratory in California and the hive
was destroyed, the department said.

“This is the farthest north that Africanized honeybees have been reported,” the health
department said.

Bob Hammon, an entomologist with Colorado State University, said the fact that the bees were
found in the spring suggests they survived through the winter.

Sometimes dubbed “killer bees” because of the aggressive way they defend colonies and hives, the
Africanized bees first arrived in the Western Hemisphere in the 1950s, when they were brought to a
facility in Brazil.

The plan was to breed them with more-docile European bees to boost honey production, but some of
the Africanized bees escaped into the wild and the first colonies reached the United States in
1990, Hammon said.

While the venom from an Africanized honeybee is no more potent than that of a European honeybee,
the risk of multiple stings makes the Africanized bees especially dangerous.